A new firmware upgrade for THEC64 and THEC64 Mini is now available. The upgrade resolves a few issues with the way files on a USB stick are displayed, and issues relating to the use of spaces and dots/periods/full stops in USB program filenames when saved states are created.
THEC64 – https://retrogames.biz/support/upgrade-thec64
THEC64 Mini – https://retrogames.biz/thec64-mini/support/upgrade-thec64-mini
Note that the v1.3.2 upgrade file serves both THEC64 and THEC64 Mini. If you have both products then you can use the same file on both devices.